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April 30, 2009 -- The FDA announced today that it will require black box labeling on Botox and similar products warning of a rare but potentially life-threatening complication when the effects of the toxin spread far beyond the injection site.

The move stems from reported hospitalizations and deaths attributed to botulism poisoning in children with cerebral palsy treated with botulinum toxin for muscle spasms.

Hospitalizations requiring ventilation have also been reported in adults treated with botulinum toxin for involuntary muscle movement and frequent neck spasms. Deaths among adults are suspected but could not be confirmed.

No serious side effects related to the distant spread of toxin have been confirmed among people who have used Botox and the related product Myobloc for cosmetic purposes.

Cosmetic Use Appears Safe

Such uses generally require much smaller doses of the toxin. Cosmetic use appears safe if the products are used as directed, an FDA official told reporters Thursday.

“If the drug is given the way it is intended, as described on the label, the risk of distant spread may well be zero,” said Ellis F. Unger, MD, of the FDA’s Center for Drug Evaluation and Research.

Unger declined to speculate on the number of hospitalizations and deaths from botulism poisoning that have occurred in Botox and Myobloc users.

But the health advocacy group Public Citizen, which petitioned the FDA for the black box warning, claims that as of early last year the drug was responsible for 180 serious adverse events and 16 deaths in the United States.

Action Affects New Botox Rival

The FDA action affects Botox and Botox Cosmetic, both sold by Allergan Inc.; Myobloc, sold by Solstice Neuroscience; and a third botulinum toxin product -- Dysport (marketed by Ipsen) -- approved just yesterday by the FDA.

The products are approved to treat uncontrolled muscle contractions in the neck and shoulder -- a condition known medically as cervical dystonia. Approved cosmetic uses include treating frown lines between the eyebrows and excessive underarm sweating.

The black box warning was just one of several moves the FDA announced regarding the products.

The manufacturers will also be required to:

Inform users in writing about the potential risk for distant spread at the time of injection.

Warn doctors and patients about the risks associated with substituting one botulism product for another. The products have different dosing units, which are incompatible, so switching products can result in dangerous overdosing.

Follow a group of children and adults using Botox, Myobloc, or Dysport off-label to treat involuntary muscle movement and submit safety data to the agency.

Although there is little concern about the safety of Botox and the other products for approved cosmetic uses when they are used as directed, the FDA is requiring these patients to be warned of the risks anyway.

Unger said these users could be at risk if they don’t use the products as directed.

“It is not unusual for patients who use these products for cosmetic purposes to get more injections at more sites than is recommended,” he said.

In a statement issued Thursday afternoon, Allergan noted that reports of serious adverse events have generally been confined to sick patients who received high doses of Botox for therapeutic, and not cosmetic, reasons.

Allergan spokeswoman Caroline Van Hove highlighted Unger’s statement to the media that no adverse events related to distant spread of the drug had been confirmed in patients using Botox as the label indicates for cosmetic reasons.

“Allergan will work with the FDA to appropriately update the label for Botox and Botox Cosmetic in light of the FDA’s conclusion,” she said. “In the interim, caution should be exercised if treating neurologically vulnerable patients with high doses of Botox.”